1. Field of the Invention
The present invention is directed to a process to restore and refurbish a turbocharger which has been subjected to corrosion, pitting or breakage from use. In particular, the present invention is directed to a process to restore and refurbish a turbocharger housing to the original finished dimensions.
2. Prior Art
Turbochargers or superchargers are known accessories to internal combustion engines. A turbocharger is driven by the engine exhaust gas to increase or boost the amount of fuel that can be burned in a cylinder, thereby increasing engine power and performance. In an aircraft engine, a turbocharger serves an additional purpose. The engine can retain its sea-level power rating at high altitudes despite a decrease in atmospheric pressure. Engine power varies with the pressure of the air entering the cylinders. Since the pressure decreases with altitude, the maximum horsepower is at sea level. For example, at an altitude of 5000 feet, the engine would deliver 85 percent power.
The turbocharger includes a center or bearing housing which supports a connecting shaft for the turbocharger. The center housing, which is often fabricated of cast aluminum, fits on an exhaust housing. The turbocharger, including its center or bearing housing, is subject to corrosion, pitting, wear and breakage from use.
Typically, after corrosion, pitting, wear or breakage, the turbocharger housing is removed and simply replaced.
Additionally, in the case of aircraft engines, because of manufacturer standards and government regulations, the turbocharger must be dismantled and inspected after a number of hours of use. As an example, it may be required to dismantle and inspect the turbocharger every 500-1800 hours of use. Once the center housing has been removed, it is difficult to align and create a good seal.
Known procedures have been used in the past to repair crank cases, cylinders or other elements of internal combustion engines. While cleaning and welding procedures are used therein, the surfaces are ground down to a new surface, which is not the original dimension.
Nowhere is it known to both grind or machine down a worn surface or surfaces and then rebuild those surfaces to their original dimensions.
It is, therefore, a principal object and purpose of the present invention to provide a process to restore and refurbish a turbocharger housing by machining selected areas, building up the selected areas in excess of finished dimensions and machining to finished dimensions.